While the design and assembly of DNA origami are straightforward, its relative novelty as a nanofabrication technique means that the tools and methods for designing new structures have not been codified as well as they have for more mature technologies, such as integrated circuits. While design approaches cannot be truly formalized until design-property relationships are fully understood, this document attempts to provide a step-by-step guide to designing DNA origami nanostructures using the tools available at the current state of the art.